* Q4 profit 35 mln rials vs 30.4 mln in 2011 - Reuters calculations
* In line with analysts' average estimate
* 2012 net profit 139.2 mln rials vs 117.5 mln rials yr-ago (Adds detail)
DUBAI, Jan 17 (Reuters) - Bank Muscat, Oman's largest lender, posted a 15.1 percent increase in fourth-quarter net profit on Thursday, Reuters calculations show, in line with the average estimate of analysts.
The bank made a quarterly net profit of 35 million rials ($90.9 million) in the three months to Dec. 31 compared with 30.4 million rials in the prior-year period, Reuters calculated from previous financial statements.
Six analysts polled by Reuters had on average estimated a fourth-quarter profit of 35 million rials.
Full-year net profits for the bank stood at 139.2 million rials, a 18.5 percent improvement on the 117.5 million rials it reported for 2011, a statement to the Omani bourse said.
The results were boosted by a 13.5 percent increase in non-interest income, which rose to 93.2 million rials, and a 8.6 percent gain in net interest income, which advanced to 230.4 million rials.
Impairments for the final three-month period of 2012 stood at 17 million rials, Reuters calculated, taking them to 57.9 million rials for the full year. This was up 11.1 and 3.2 percent respectively on the corresponding period of 2011.
Loans and advances rose to 5.6 billion rials at the end of 2012, up 16.2 percent from 4.82 billion rials at the same point in 2011.
Deposits increased 10.9 percent in 2012, the bank said, rising to 5.38 billion rials from 4.85 billion rials at the end of 2011.
Earlier this week, Bank Muscat said it had received a licence from the country's central bank to commence Islamic banking operations under its Meethaq Islamic Banking brand.
Bank Muscat shares rose 0.7 percent in early Muscat trade. ($1 = 0.3850 Omani rials) (Reporting by David French; Editing by Dinesh Nair)